This study explores the relationship between growth hormone (GH) secretion, sleep stage regulation, and cognitive functioning in children. Previous studies in both adult humans and animals have demonstrated a feedback mechanism between GH, slow wave sleep and REM sleep (SWS), but a less demonstrable effect on cognitive functioning. In this study we wish to 1) further establish the concept of a spectrum disorder of growth hormone deficiency by examining the sleep stage changes of children with neurosecretory dysfunction; 2) test the negative feedback hypotheses by comparing SWS and REM sleep in these children before and during treatment with exogenous GH; and 3) confirm the hypothesis that GH has a positive effect on immediate recall and visual spatial abilities in children. Nine children are being studied both before and during treatment with exogenous GH using all night somnography, a verbal memory measure and the Spatial Relations and Perceptual Speed Scales of the Primary Mental Abilities Test.